Diaphbagm-horn and means fob operating the same



, A. L. McMURTRYg DIAPHRAGM HORN AND MEANS FOR OPERATING THE SAME.

APPLICATION FILED FEB. 6.1

1,309,764. I v Patented July 15, 1919.

- 2 SHEETS-SHEET INVENTOR WI NESSES:

L24 I! BY A. L..McMURTRY.

DIAPHRAGM HORN AND MEANS FOR OPERATING THE SAME.

v APPLICATION FILED FEB. 6,1912.

2 SHEETSSHEET' 2.

T"! COLUIBIA WRAP" 00., WAIIIINGTON, D. C.

Patented July 15, 1919.

p EN' FEE ALnnnnir yrnnr-rar, or SQIIND Brine-n, connne'rrco'r, ASSIGNOB, BY Mnsnn ASS-IGN- N J'T L L M N ELL MAN U c mune. c sr mrrn or DELAWARE.

. Specification of Letters I atent.

Patented. July 15, 1919.

Application filed Februaryfi, 1912. Serial No. 675,800.

To'cZZ whom it'may concern: 1

Be it known that I, ALDEN MCMURTRY, a citizen of the United States, and a resident of Sound Beach, county of Fairfield, State of Connecticut, have invented certain new and useful Forms of Diaphragm-Horns and Means for Operatingthe Same, whereof the following is a specification.

My invention especially relates to that type of horn or warning signal most commonly used on automobiles, motor boats and the like wherein a vibratory diaphragm is used to produce the sound desired. My in vention comprises various novel forms of construction of such horns or signals and operating mechanism therefor and its object is to provide means for obtaining an effective vibratory movement of a diaphragm efliciently and with a minimum of injurious effect on the diaphragm.

I will describe my invention in the following specification and will point outthe novel features thereof in appended claims.

In the drawings herewith, wherein are shown certain forms of embodiment of my invention Figure 1 represents a sectional view in side elevationof a horn embodying'my invention the operating mechanism being shown in elevation.

ig. 2 represents a front view in elevation of the operating mechanism shown in Fig. 1.

Fig. 3 represents on an enlarged scale a detail view of a portion of the construction of Figs. 1 and 2.

Fig. 1 represents a sectional view in side elevation of another form of embodiment of my invention the operating mechanism being in elevation.

Fig. 5 represents a detail view of a portion of the driving mechanism of Fig. 1.

F 6 represents a view in front elevation of a portion of the operating mechanism of a further modified form of embodiment of my invention. Y

Figs. 7 8, 9 and 10 represent detail views of parts of the mechanism shown in Fig. 6.

Like characters of reference denote like parts in all the figures of the drawings herewith.

Turning now to a description of my invention in detail, and considering the embodi'm ent thereof shown in Figs. 1,. 2, and 3,

there is shown a'horn comprising the cylindrical casing 10 with back plate 11, preferably integral therewith, and front plate 12 suitably secured thereto. A circular diaphragm casing 13 is secured to front plate a by screws .14 passing through the front plate and a flange onthe open side of casing 13, the casing 10 being extendedto cover the line of joinder of diaphragm casing and front plate. From a centrally located opening in casing 18 extends a projector or resonator 15 of any desired and convenient form. Within the casing 13 is mounted a circular diaphragm 16 preferably of metal held at its edge betweenan annular shoulder on the interior of the easing and a retaining ring 17 and secured in position by screws 18. Passing through the center ofdiaphragm 16 is a spindle 19, one end of which is rigidly afiixe'd to the diaphragm near the center thereof. This spindle extends to the rear through an opening in front plate 12 and through a spring 20, preferably flat as shown, the opposite end of the spindle being formed with a threadedportion on which are mounted-nuts 21 adapted to be adjusted in position on the spindle to bear against opposite sides of spring 20 as desired. Spring 20 is mounted, within the casing 10 in the following manner: A pedestal block 23 is secured .tothe front plate 12 by one of the screws 14, the rear face of the mounting block being formed with a curved recess, the upper end of the spring 20 rests on the flat surface of a bearing block 22 which is provided on the opposite side with a projecting curved face adapted to fit in the curved recess of block 23. The mounting and bearing blocks and spring are secured together by screws 24 passing therethrough and threaded in block 23. The holes through which the screws pass inblock 22 are enlarged to permit of adjustment hereafter to be described.

Mounted on front plate 12 adjacent the top thereof is a bracket 25 which supports a rotatable shaft 26 extending through the rear plate of the casing and provided with a knob or handle 27 of any desired form by whichthe shaft 26 may be turned. On shaft 26 is mounted'a circular bevel gear 28, of as large diameteras the size of the structnre will permit,which gear engages 'a small bevel gear wheel 31 at one end of shaft 30 rotatable in supports 29. At the opposite end of shaft 30 is an enlarged bevel gear 32 engaging a small gear 33 on'sha-ft 34 whlch is rotatable in supports 35'. On shaft 34 preferably at the center thereof is mounted a toothed pinion or striking cog 36, the teeth of which are adapted to contact with the free lower end of spring 20 which end as shown ispreferabIy curved and of narrowed width to permit of more compact and ellicient construction.

From thewabove description it will readily be seen that the turning of the handle 27 at even a moderate rate of speed operates to cause a rapid rotation of thestriking pinion 36 by reason of the train of multiplying gears interposed between said'parts. The striking wheel inits rotation contacts with the spring 20and through it and the spindle 19 ef fects a vibratory movement of diaphragm 16 to produce the desired sound. However it is of greatest importance that the adjustment of the parts be such as to cause the vibrationsthus set up in the diaphragm to be the same as the natural periodicity of the diaphragm itself. Thus a sound or note of desired pitch is produced with the least possible expenditure of power and absence of wear on parts; it is for this reason I have provided the novel means of adjustment, the construction of which has heretofore been described. It will be. seen that the nuts 21 on spindle 19 bear upon the spring 20 and may be adjusted to move the lower end of the spring so that the degree of contact both in length of time and in pressure between the spring and the teeth of the striking pinion 36 may be as desired. In like manner it will be seen that by the tightening of one of the screws 24 and loosening of the other the bearing block 22 may be tilted or rocked so that any desired tension may be secured on that portion of the spring between the bearing block and the spindle 19. The spring tongue normally tends to vibrate with nodal points at the spindle and at the bearing block 22, so that the spring in vibrating forms three-quarters of a wave. The natural frequency of vibration of the spring tongue may be modified and attuned to that of the diaphragm. by means of the adjustments above referred to. By permanently bowing the portion of the spring between the bearing block and the spindle by tilting the support of the spring on the bearing block, the spring may be effectively stiffened and its rate of, vibration increased. This may be accomplished without materially changing the position of the tip of the spring as the connection between the spindle and the spring may be adjusted to correspond to the variation in position of the tip which would result from a permanent bowingor bending of the spring between its two points of sup port. In the use of these means of adjustment as described the desired pitch and volume of tone may readily be secured in the most efficient and economical manner.

In Fig. 4 is shown an embodiment of my invention wherein is shown a modification in the construction of the driving mechanism. The construction of casings, diaphragm, and actuating mechanism are similar in construction to those shown in Figs. 1, 2 and 3 with the exceptions that a multiplying train of gears is not necessary, and the casing is made with an enlarged upper portion to accommodate change in driving mechanism to be described. Secured to the inside of the casing 10 preferablyat the top is a support 40 in the bottom of which is journaled a short shaft bearing at one end the half 41 of a toothedclutch and at the other end the cylindrical member 42. A short shaft is journaled in the lug 25. The free end of this shaft carries gear 28 and has securedthereto a member 43 centrally mounted to provide two projecting lugs. At

the end of each lugis pivotedan arm 44 formed with an enlarged end portion the opposing faces of which are each formed with an inwardly curved surface adapted to rest upon the surface of cylindrical member 42, as shown in Fig. 5. The arms 44 are drawn together and their curved end surfaces pressed against member 42 by means of a spring 45 the tension of which may be adjusted as desired bymeans of the screw and nut 46. From outside'the casing a fiexible drive 47 leads from a suitable source of power, such as the fly wheel of the engine of an automobile, terminating within the casing in a short shaft 48 on the end of which is feathered a collar 49 integral with which is the second half of the toothed clutch. The collar 49 is pivotally attached to the upper end-of a lever arm 50 pivoted at its lower end at the bottom of the casing} By means of a rod 51 secured to lever arm 50, projecting through the casing and provided with a handle the collar and half clutch 49 may be moved on shaft 48 to either engage the clutch with or disengage it from theother half 41 of the clutch. 'The clutch being in engagement it will be evident that the power will be applied, through the frictional engagement of member 42 and arms 44, to operate the actuating mechanism of the horn. The tension of the spring 45 which draws arms 44 together is so adjusted that, at a certain determined and desired speed, the centrifugal force caused by the rotation of the member :43, on which the arms are mounted, will act to force the arms outward against the action of the springand thus release the frictional engagement of, 7

their curved end surfaces with the rotating member 42. Inthis manner the rate of speed. at which the actuating'mechanism of the horn is driven may always bejkept at or below a "desired maximum. Thus I have provided that the rate ofspeed of the aotuating mechanism shall never be so'rapid as to become out of step with the desired periodicity or rapidity of vibration of thediaphragm even when the rate of speed of the driving mechanism is too high.

In Fig. 6 I have shown another form of construction whereby the actuating mechanism may be kept in step with the desired rapidity of vibration of "the diaphragm whatever may be the rate of speed of the driving mechanism. The mechanism shown is that within the horn casin'g'f'A shaft 60 driven from an electric motor or from the engine of an automobile or from some other suitable source of power, is provided with a gear 61 engaging gear 6'2 at one end of a shaft 63 rotatably mounted inisupports 64. Adjacent one end of the shaft 63 a'collar 65 is mounted thereon in a fixed position and adjacent its opposite end there is feathered on the shaft a collar 66 bearing the successive toothed striking cogs 67, 68, 69 and70. The cogs, shown in detail in Figs. 7, '8, 9, and 10, each bear a difierent' number of teeth, the first cog 67 having a'comparatively great number of close set teeth and the number being reduced preferably by half in each successive cog until the last one has preferably only two teeth. In the normal position of parts the spring 20', through which the diaphragm is vibrated, rests on the'cog 67 which has-the greatest number of teeth. The collars 65 and 66 are each pro vidc-d with two projecting lugs 71 and an arm 72 is pivoted to each lug; The corresponding arms on the lugs of each collar extend toward each other and are pivotally joined at their free ends, a weight/'73 being provided at the point of joinder of'each two arms; the points of joinder of each two arms are connected, on the side opposite to that on which the weights are mounted, by a spiral spring 74 provided with nut and screw means for adjusting the'tension. In this manner a governor is formed connecting the two collars 65 and 66 the governor weights being predetermined and the tension of the spring so adjusted that upon rotation of the shaft 63' at a'low rate of speed the governor will not operate to move the collar- 66, which as hasbeen stated is slidably mounted on the shaft.

hen the speed of rotation of shaft 63 becomes greater the continued contacting of the many toothed cog 67 with spring 20 would produce a too rapid vibration of the diaphragm. At this point centrifugal force acts upon the governor to cause a movement of the collar 66 upon the shaft 63 and by means of this movement the next cog '68 hearing a smaller number of teeth is brought into position in contact with the-spring 20. It will thus be seenthat an increasing speed.

of rotation of shaft 63 will bring successive striking cogs into contact with the spring 20 and by "means of the successively diminish ing number of teeth on the cogs the periodicity or rapidity of vibration of the horn diaphragm will not be raised above a "desired, predetermined rate irrespective of the speed of the driving power which causes ro tation of the striking cog shaft.

I have herein shown several methods for obtaining vibrations of a diaphragm at desired rates or periodicities. It is also important to construct the projector 15 of such shape and proportions that it will act as a resonator. That is, I so proportion this element that the sound waves produced therein will be augmented. The cotSrdination between the periodicity of the diaphragm, the means for vibrating it at a rate corresponding'with its periodicity and proportioning the projector to form a resonator, gives a higher eflici'ency than is obtained with many of the devices heretofore used.

l/Vhat I claim is? 1. In a horn or signal, a vibratory diaphragm, an elastic member fixed at one end, a spindle on the diaphragmconnected to the elastic member intermediate the length of the latter, means for actuating the elastic member to cause vibration of the diaphragm, said means comprising a toothed wheel adapted to contact with the elastic member, and means for adjusting the position of the elastic member in relation'to the wheel.

2. In a horn or signal, a vibratory diaphragm, an elastic member connected with said diaphragm, means for actuating the elastic member to cause vibration of the diaphragm, said means comprising a rotatable cam wheel adapted to contact with the elastic member, and automatic means adapted to move the cam wheel out of contacting position when the speed of rotation of the cam wheel exceeds a predetermined rate.

3. In a horn or signal, a vibratory diaphragm, and means for actuating the diaphragm, said means comprising a plurality of toothed wheels having different numbers of teeth, and means for moving the wheels to bring any one of them into operative position.

4. In a. horn or signal, a vibratory diaphragm, and means for actuating the diaphragm, said means comprising a plurality of toothed wheels having different numbers ofteeth, and automatic means dependent upon the rate of rotation of the wheels for bringing any one of said wheels into operative position.

5. In a horn or signal, a vibratory diaphragm, an elastic member connected with the diaphragm, means for actuating the clastic member to cause vibration of the diaphragm, said means comprising a plurality of rctatabie toothed. wheels-liming. different phragm and the support at the first mennumbers of teeth adapted to contact with the elastic member, and automatic means adapted to move said wheels successively into contacting position with the elastic member as the speed of rotation of the wheels increases.

6. In a motor driven vehicle, the combination with a driven shaft, of a plurality of disks on the shaft, said disks having projections, a diaphragm holder, a diaphragm held in said holder, and means for bringing said diaphragm and either of the disks into operative engagement substantially as set forth.

7. A horn or signaling device comprising a diaphragm, a plurality of rotary cams in axial alinement and rigidly connected together, and means adapted to operatively engage with one of said cams to vibrate said diaphragm, said cams and said diaphragm being relatively movable to cause vibration of the diaphragm by any one of said cams.

8. A horn or signaling device including a diaphragm, an elongated spring disposed approximately parallel thereto and having one end supported adjacent to the periphery of the diaphragm and having the opposite end free, connections between the central portion of said diaphragm and said spring intermediate of the ends of the latter, said connections permitting an adjustment of said spring toward and from said diationed end of said spring permitting a bowing or bending of the spring intermediate of said support and said connections and means engaging with the free end of said spring to vibrate the latter and said diaphragm.

9. In a horn or signal, a vibratory diaphragm, an elastic member connected to said diaphragm and presenting a free end, a rotary cam engaging with said free end to vibrate said member and said diaphragm, and means for adjusting said member toward and from said diaphragm at its point of connection with the latter.

10. In a horn or signaling device, a vibratory diaphragm, an elastic member, means for clamping a portion of said mem ber rigid independently of the diaphragm, means for clamping a second portion to a vibratory portion of the diaphragm, and a rotary cam engaging with said elastic member to effect vibration of the latter, one of said clamping means permitting an adjustment of the engagement of said elastic member and said cam, by bowing the portion of said member intermediate of said clamped portions.

11. In a horn or signaling device, a vibratory diaphragm, an elastic member, means for clamping a portion of said member rigid independently of the diaphragm, means for clamping a second portion to a vibratory portion of the diaphragm, and a rotary cam engaging with said elastic member to effect vibration of the latter, one of said clamping means permitting an adjustment of the engagement of said elastic member and said cam, by varying the distance between said diaphragm'and said elastic member. A

12. In a horn or signaling device, a diaphragm, an elongated spring disposed approximately parallel thereto, and having one end supported adjacent to the periphery of the diaphragm and having the opposite end free, rigid connections between the central' portion of said diaphragm and said spring intermediate of the ends of the latter, and means engaging with said free end to vibrate said spring and said diaphragm.

13. A horn or signaling device including a diaphragm, a casing supporting said diaphragm, a shaft substantially parallel to said diaphragm and mounted in spaced bearings in said casing, a cam on said shaft for effecting the vibration of the diaphragm, means for shifting said cam axially in one direction to bring into operation difierent peripheral portions thereof and a spring normally tending to move the cam axially in the opposite direction.

- 14. A horn or signaling device including a diaphragm, a casing supporting said diaphragm, a shaft substantially parallel to said diaphragm and supported in said casing, a rotor carried by said shaft and presenting a plurality of diflerent'series of poripheral projections, a member engaging with said projections for effecting vibration of said diaphragm upon the rotation of said rotor, said rotor having an operative surface of materially greater width than the contacting portion of said member and means for shifting said rotor axially to bring different series of peripheral projections into engagement with said member. 7

15. A horn or signaling device including a diaphragm, a casing supporting said dia phragm, a shaft substantially parallel to said diaphragm and supported in said cas-' ing, a rotor carried by said shaft and presenting peripheral projections varying in character endwise thereof, a member engaging with said projections for effecting vibration of said diaphragm upon the rotation of said rotor, said rotor having an operative surface of materially greater width than the contacting portion of said member, means for shifting said rotor axially to bring different portions of this peripheral surface into engagement with said member, and a spring normally tending to move said rotor in the opposite direction.

16. A born or signaling device including a diaphragm, a casing supporting said diaphragm, a shaft substantially parallel to said diaphragm and supported in said casing, a rotor carried by said shaft and presenting a series of peripheral projections, a member engaging with said projections for effecting vibration of said diaphragm upon the rotation of said rotor, said rotor having an operative surface of materially greater width than the contacting portion of said member and having the projections varying in character along said width, and means for shifting said rotor axially to bring different portions of this peripheral surface into engagement with said member, the axial snifting of said rotor being performed substantially simultaneously with changes in speed thereof.

17. A horn comprising a ring-like casing, an amplifier attached thereto, a flexible diaphragm mounted in the casing, a pinion rotatably mounted in the casing, means for rotating the pinion, a resilient arm disposed Within the casing parallel to the diaphragm and having one end permanently connected to the casing, said arm having its other end engaging said pinion, a screw member ar- 7 ranged within the casing and having one of its ends axially engaging the diaphragm, the opposite end thereof being passed through the resilient arm and adjusta bly receiving the latter, and means for locking said arm in adjusted position upon the screw.

18. A horn comprising a casing, a flexible diaphragm mounted in the casing, a resilient arm disposed within the'casing parallel to the diaphragm and having one end permanently connected to the casing, a screw member arranged within the casing and having one of its ends axially engaging the diaphragm, the opposite end thereof being passed through the resilient arm and adjustably receiving the latter, means for lock ing said arm in adjusted position upon the screw, and means engaging with the opposite end of said arm for vibrating said arm to vibrate said diaphragm.

ALDEN L. MGMURTRY. Witnesses:

F. GRAVES, G. QUIMBY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0. 

